RESUMO
OBJECTIVE: To assess the healing outcomes at buccal dehiscence defects after 4 months following implant placement immediately into extraction sockets (IPIES) and filled with a mixture of synthetic hydroxyl apatite (HA) 60% and ß-tri-calcium phosphate (ß-TCP) 40% in comparison with leaving a blood clot. MATERIAL AND METHODS: Eight Labrador dogs were used, and an implant was placed immediately following tooth extraction into the distal alveolus of the third premolars, bilaterally. Standardized buccal defects, 8 mm in depth and 4 mm in width at the coronal and 2 mm in width at the apical outlines were created. A mixture of synthetic HA 60% and ß-TCP 40% was used to fill the defects at the test sites, while the control sites were left unfilled. Collagen membranes were used to cover the defects at both sides, and a non-submerged healing was allowed. After 4 months of healing, biopsies were obtained and processed for morphometric analysis. RESULTS: A vertical gain in the extent of the bony crest and of osseointegration levels of 4.2 ± 2.4 and 3.3 ± 2.1 mm at the test sites and of 5.0 ± 0.8 and 4.6 ± 1.0 mm at the control sites, respectively, were observed. BIC% within the buccal defects reached similar levels (37-42%) both at test and control sites. None of the means of the variables differed significantly between the two groups. New bone formation within the defects was higher, and the percentage of the connective tissue was lower at the control (65.7 ± 11.7% and 2.5 ± 3.3%, respectively) compared to the test sites (16.8 ± 11.3% and 48.9 ± 29.5%, respectively). These differences were statistically significant. CONCLUSIONS: The use of a mixture of synthetic HA 60% and ß-TCP 40% to fill surgically created buccal dehiscence defects at IPIES sites covered with a collagen membrane did not improve osseointegration in the defect area.
Assuntos
Implantes Dentários , Hidroxiapatitas/farmacologia , Carga Imediata em Implante Dentário , Deiscência da Ferida Operatória/tratamento farmacológico , Cicatrização/fisiologia , Animais , Dente Pré-Molar , Biópsia , Colágeno/farmacologia , Cães , MandíbulaRESUMO
AIM: To study the sequential events in osseointegration at implants with highly hydrophilic surfaces. MATERIAL AND METHODS: All premolars and the first molars were bilaterally extracted in 12 Beagle dogs. After 3 months, full-thickness flaps were elevated and two different implants systems with various surfaces were randomly installed in the edentulous premolar region in one side of the mandible. One surface was acid etched and further modified with calcium ions (UnicCa(®)), while the other was sandblasted with large grits and acid etched (SLActive(®)). The flaps were sutured to allow a fully submerged healing. The surgery on the other side of the mandible and the sacrifices were planned in such a way to obtain biopsies representing the healing after 1, 2, 4, and 8 weeks (n = 6 per period). RESULTS: After one week of healing, new bone apposition was found at both surfaces with percentages of 6.9 ± 3.3% and 6.1 ± 4.6% at UnicCa(®) and SLActive(®), respectively. After 2 weeks, the percentages had increased to 29.1 ± 11.9% and 21.6 ± 14.3%, respectively. After 4 and 8 weeks of healing, mean values of 46.3 ± 7.3% and 58.7 ± 15.1% at UnicCa(®) and 51.2 ± 16.1% and 68.9 ± 15.4% at SLActive(®) surfaces were found, respectively. None of the differences in percentages were statistically significant. Concomitantly, the old bone was resorbed at both surfaces from about 21-22% after 1 week to about 4-6% after 8 weeks of healing. CONCLUSIONS: The osseointegration process onto moderately rough titanium implant surfaces of high hydrophilicity was very similar for two implant systems that were both nanotechnologically modified.
Assuntos
Implantação Dentária Endóssea/métodos , Implantes Dentários , Osseointegração/fisiologia , Cicatrização/fisiologia , Condicionamento Ácido do Dente , Animais , Dente Pré-Molar , Cães , Interações Hidrofóbicas e Hidrofílicas , Mandíbula/cirurgia , Teste de Materiais , Dente Molar , Propriedades de Superfície , Retalhos Cirúrgicos , TitânioRESUMO
PURPOSE: The aim of this paper was to study the sequential healing of bone tissues at implants with different configuration and different modified surfaces. MATERIALS AND METHODS: Twelve Beagle dogs were used. Extractions of all teeth from the second premolar to the first molar were performed in both sides of the mandible. After 3 months, full-thickness flaps were elevated and two implants of different systems and with different surfaces were randomly installed in the premolar region in one side of the mandible. One surface was acid etched and further modified with calcium ions (BTI unicCa®), the other was sandblasted and acid etched plus a nanometer calcium phosphate deposition (3i T3®). The flaps were sutured to allow a fully submerged healing. The surgery on the other side of the mandible and the sacrifices were planned in such a way to obtain biopsies representing the healing after 1, 2, 4, and 8 weeks (n = 6 per period). RESULTS: After 1 and 2 weeks of healing, the mean values of new bone apposition on the implant surfaces were 5.9 ± 3.3% and 29.8 ± 16.0% at BTI unicCa and 4.6 ± 3.3% and 12.4 ± 5.6% at 3i T3, respectively. After 4 and 8 weeks, the percentage increased, being 49.4 ± 8.1% and 63.6 ± 7.3% at BTI unicCa and 40.3 ± 10.0% and 47.3 ± 20.2 at 3i T3, respectively. Differences statistically significant between the two surfaces were found only at the 2- and 4-week observation periods. Concomitantly, the old bone was resorbed at both surfaces from about 15-17% after 1 week to about 4-6% after 8 weeks of healing. CONCLUSION: Moderately rough surfaces modified with calcium ions or discrete calcium phosphate nanocrystalline deposition showed similar patterns of sequential healing. Higher new bone percentages were found at BTI unicCa compared with the 3i T3 implants, the difference being statistically significant at 2 and 4 weeks observation.
Assuntos
Fosfatos de Cálcio , Cálcio , Implantação Dentária Endóssea , Osseointegração , Titânio , Animais , Implantes Dentários , Planejamento de Prótese Dentária , Cães , Mandíbula/cirurgia , Propriedades de SuperfícieRESUMO
OBJECTIVE: To compare peri-implant soft- and hard-tissue integration at implants installed juxta- or sub-crestally. Furthermore, differences in the hard and soft peri-implant tissue dimensions at sites prepared with drills or sonic instruments were to be evaluated. MATERIAL AND METHODS: Three months after tooth extraction in six dogs, recipient sites were prepared in both sides of the mandible using conventional drills or a sonic device (Sonosurgery(®)). Two implants with a 1.7-mm high-polished neck were installed, one with the rough/smooth surface interface placed at the level of the buccal bony crest (control) and the second placed 1.3 mm deeper (test). After 8 weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation. RESULTS: The buccal distances between the abutment/fixture junction (AF) and the most coronal level of osseointegration (B) were 1.6 ± 0.6 and 2.4 ± 0.4 mm; between AF and the top of the bony crest (C), they were 1.4 ± 0.4 and 2.2 ± 0.2 mm at the test and control sites, respectively. The top of the peri-implant mucosa (PM) was located more coronally at the test (1.2 ± 0.6 mm) compared to the control sites (0.6 ± 0.5 mm). However, when the original position of the bony crest was taken into account, a higher bone loss and a more apical position of the peri-implant mucosa resulted at the test sites. CONCLUSIONS: The placement of implants into a sub-crestal location resulted in a higher vertical buccal bone resorption and a more apical position of the peri-implant mucosa in relation to the level of the bony crest at implant installation. Moreover, peri-implant hard-tissue dimensions were similar at sites prepared with either drills or Sonosurgery(®).
Assuntos
Perda do Osso Alveolar/patologia , Reabsorção Óssea/patologia , Implantação Dentária Endóssea/métodos , Implantes Dentários , Mandíbula/cirurgia , Animais , Biópsia , Dente Suporte , Implantação Dentária Endóssea/instrumentação , Cães , Osseointegração , Extração DentáriaRESUMO
OBJECTIVE: To compare peri-implant tissue healing at implants installed in sites prepared with conventional drills or a sonic device. MATERIAL AND METHODS: In six Beagle dogs, the mandibular premolars and first molars were extracted bilaterally. After 3 months, full-thickness muco-periosteal flaps were elevated and recipient sites were prepared in both sides of the mandible. In the right side (control), the osteotomies were prepared using conventional drills, while, at the left side (test), a sonic device (Sonosurgery(®)) was used. Two implants were installed in each side of the mandible. After 8 weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation. RESULTS: The time consumed for the osteotomies at the test was more than double compared to the conventional control sites. No statistically significant differences were found for any of the histological variables evaluated for hard and soft tissue dimensions. Although not statistically significant, slightly higher mineralized bone-to-implant contact was found at the test (65.4%) compared to the control (58.1) sites. CONCLUSIONS: Similar healing characteristics in osseointegration and marginal hard tissue remodeling resulted at implants installed into osteotomies prepared with conventional drills or with the sonic instrument (Sonosurgery(®)).
Assuntos
Implantação Dentária Endóssea/métodos , Osteotomia/métodos , Procedimentos Cirúrgicos Ultrassônicos/métodos , Cicatrização/fisiologia , Animais , Biópsia , Cães , Desenho de Equipamento , Mandíbula/cirurgia , Osteotomia/instrumentação , Retalhos Cirúrgicos , Extração Dentária , Procedimentos Cirúrgicos Ultrassônicos/instrumentaçãoRESUMO
PURPOSE: N-butyl-2-cyanoacrylate (NB-Cn) is an alternative method for onlay graft fixation and might be efficient for preserving the graft volume. Our aim was to analyze the gene expression and mineralized tissue variations of calvarial bone grafting fixed in the mandible with either NB-Cn or a titanium screw (TiS). MATERIALS AND METHODS: New Zealand rabbits had bilateral calvarial grafts fixed at both sides of the mandible with either NB-Cn or a TiS. The rabbits were sacrificed at 4 and 8 days, and micro-computed tomography analysis was performed. For molecular analysis, the gene expression of interleukin-6, interleukin-10, and tumor necrosis factor-α was assessed. Quantification using real-time polymerase chain reaction was performed. Statistical analysis was performed using the paired Student t test (P < .05). RESULTS: Bone graft fixation with NB-Cn promoted superior volume and density preservation. The percentage of mineralized tissue at the center portion and border of the graft was very similar (NB-Cn, 50.6% ± 8.3% and 50.3% ± 10.6%, respectively) and superior than in the TiS group (32.5% ± 3.5% and 33.8% ± 6%, respectively). Genes from the NB-Cn group were upregulated compared with those in the TiS group at the initial phases of bone healing (4 days), with the profile reversed at the 8-day point. At day 8, the osteoclastogenesis-related genes were upregulated in the TiS group. CONCLUSIONS: Onlay bone grafts fixed with screws induced more inflammation during the initial remodeling process than did NB-Cn. The differences in the incorporation into the host bed suggest that the use of adhesives for graft fixation will promote superior volume and density preservation.
Assuntos
Parafusos Ósseos , Transplante Ósseo/métodos , Embucrilato/uso terapêutico , Mandíbula/cirurgia , Animais , Autoenxertos/transplante , Materiais Biocompatíveis/química , Densidade Óssea/fisiologia , Remodelação Óssea/fisiologia , Transplante Ósseo/instrumentação , Calcificação Fisiológica/fisiologia , Imageamento Tridimensional/métodos , Interleucina-10/análise , Interleucina-6/análise , Masculino , Osteoclastos/patologia , Coelhos , Distribuição Aleatória , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Tempo , Titânio/química , Fator de Necrose Tumoral alfa/análise , Cicatrização/fisiologia , Microtomografia por Raio-XRESUMO
The aim of this study was to assess the osteoconductive and osteogenic properties of processed bovine dentin using a robust rabbit calvarial defect model. In total, 16 New Zealand White rabbits were operated to create three circular defects in the calvaria. One defect was left unfilled, one filled with collected autogenous bone, and the third defect was filled with the dentin-based bone substitute. Following surgery and after a healing period of either 1 or 6 weeks, a CT scan was obtained. Following sacrificing, the tissues were processed for histological examination. The CT data showed the density in the area grafted with the dentin-based material was higher than the surrounding bone and the areas grafted with autologous bone after 1 week and 6 weeks of healing. The area left unfilled remained an empty defect after 1 week and 6 weeks. Histological examination of the defects filled with the dentin product after 6 weeks showed soft tissue encapsulation around the dentin particles. It can be concluded that the rabbit calvarial model used in this study is a robust model for the assessment of bone materials. Bovine dentin is a biostable material; however, it may not be suitable for repairing large 4-wall defects.
RESUMO
AIM: To evaluate the integration of implants installed using a surgical guide in augmented sites with autologous bone or deproteinized bovine bone mineral (DBBM) blocks, concomitantly with a collagen membrane. MATERIAL AND METHODS: Mandibular molars were extracted bilaterally in six Labrador dogs, the buccal bony wall was removed, and a box-shaped defect was created. After 3 months, flaps were elevated, a bony graft was harvested from the ascending ramus, and secured to the lateral wall of the defect by means of screws. In the left mandibular side, a DBBM block was fixed into the defect. A resorbable membrane was applied at both sides, and the flaps were sutured. After 3 months, flaps were elevated, and a customized device was used as surgical guide to prepare the recipient sites in the interface between grafts and parent bone. One implant was installed in each side of the mandible. After 3 months, biopsies were harvested, and ground sections were prepared for histologic evaluation. RESULTS: One autologous bone block graft was lost before implant installation. The width of the alveolar crest at the test sites (DBBM) was 5.4 ± 1.2 mm before, 9.4 ± 1.2 mm immediately after grafting, and 9.3 ± 1 mm at implant installation. At the control sites (autologous bone), the corresponding values were: 5.2 ± 1, 9 ± 1.2, and 8.7 ± 0.9 mm, respectively. All implants installed were available for histologic evaluation (n = 5). The autologous bone grafts, rich in vessels and cells, were integrated in the parent bone, and only little non-vital bone was found. The BIC% was 56.7 ± 15.6% and 54.2 ± 13.2% at the buccal and lingual aspects, respectively. At the test sites, the DBBM appeared to be embedded into connective tissue, and very little newly formed bone was encountered within the grafts. The BIC% was 5.8 ± 12.3% and 51.3 ± 14.2% at the buccal and lingual aspects, respectively. CONCLUSIONS: Autologous bone blocks used to augment the alveolar bony crest horizontally allowed the complete osseointegration of implants installed after 3 months of healing. However, similar blocks of DBBM did not promote osseointegration, although the installed implants were stable owing to the osseointegration in the sites of the parent bone.
Assuntos
Transplante Ósseo/métodos , Implantação Dentária Endóssea/métodos , Implantes Dentários , Cicatrização/fisiologia , Aumento do Rebordo Alveolar/métodos , Animais , Biópsia , Parafusos Ósseos , Substitutos Ósseos/farmacologia , Cães , Membranas Artificiais , Osseointegração , Retalhos Cirúrgicos , Transplante AutólogoRESUMO
A Implantodontia revolucionou a Odontologia moderna e se tornou a primeira opção de tratamento reabilitador para os casos de desdentados parciais ou totais. Nesse processo, os avanços tecnológicos e científicos da técnica proporcionaram níveis de sucesso próximos a 100% e com alta previsibilidade. Apesar dos grandes avanços, ainda temos desafios em pontos específicos, como desenho dos implantes, biofuncionalização da superfície do implante, manutenção do nível ósseo e terapias previsíveis para implantes com perda óssea peri-implantar progressiva. Atualmente, busca-se ampliar as possibilidades de indicações dos implantes para além dos casos tecnicamente favoráveis, reduzindo-se o tempo de cicatrização e de carregamento do implante, bem como reestabelecendo um padrão estético que mimetiza a dentição natural com previsibilidade, estabilidade e saúde por tempo indeterminado
Implantology revolutionized the modern dentistry and became the first choice in the rehabilitation of partially dentate or edentulous patients. During this process, technologic and scientific advances granted success rate up to 100% with high predictability. Despite the great advances, we are still facing specific key challenges regarding implant design, surface biofunctionalization, bone level preservation and predictable therapies to deal with progressive cervical bone loss. Currently, new possibilities have been explored to expand dental implant treatment for those cases further than the ideal condition, achieving reduced healing and loading times, and also to reconstruct an aesthetic profile mimicking the natural dentition together with confidence, stability, and long-term healthiness.
Assuntos
Implantes Dentários , Peri-Implantite , Engenharia TecidualRESUMO
BACKGROUND: Previous studies have pointed out that the mere elevation of the maxillary sinus membrane promotes bone formation without the use of augmentation materials. PURPOSE: This experimental study aimed at evaluating if the two-stage procedure for sinus floor augmentation could benefit from the use of a space-making device in order to increase the bone volume to enable later implant installation with good primary stability. MATERIALS AND METHODS: Six male tufted capuchin primates (Cebus apella) were subjected to extraction of the three premolars and the first molar on both sides of the maxilla to create an edentulous area. The sinuses were opened using the lateral bone-wall window technique, and the membrane was elevated. One resorbable space-making device was inserted in each maxillary sinus, and the bone window was returned in place. The animals were euthanatized after 6 months, and biopsy blocks containing the whole maxillary sinus and surrounding soft tissues were prepared for ground sections. RESULTS: The histological examination of the specimens showed bone formation in contact with both the schneiderian membrane and the device in most cases even when the device was displaced. The process of bone formation indicates that this technique is potentially useful for two-stage sinus floor augmentation. The lack of stabilization of the device within the sinus demands further improvement of space-makers for predictable bone augmentation. CONCLUSIONS: It is concluded that (1) the device used in this study did not trigger any important inflammatory reaction; (2) when the sinus membrane was elevated, bone formation was a constant finding; and (3) an ideal space-making device should be stable and elevate the membrane to ensure a maintained connection between the membrane and the secluded space.
Assuntos
Implantes Experimentais , Seio Maxilar/cirurgia , Mucosa Nasal/fisiologia , Osteogênese , Levantamento do Assoalho do Seio Maxilar/instrumentação , Implantes Absorvíveis , Animais , Cebus , Masculino , Levantamento do Assoalho do Seio Maxilar/métodosRESUMO
PURPOSE: The aim of the present study was to investigate the healing, integration, and maintenance of autogenous onlay bone grafts and implant osseointegration either loaded in the early or the delayed stages. MATERIALS AND METHODS: A total of 5 male dogs received bilateral blocks of onlay bone grafts harvested from the contralateral alveolar ridge of the mandible. On one side, the bone block was secured by 3 dental implants (3.5 mm x 13.0 mm, Osseospeed; AstraTech AB, Mölndal, Sweden). Two implants at the extremities of the graft were loaded 2 days after installation by abutment connection and prosthesis (simultaneous implant placement group); the implant in the middle remained unloaded and served as the control. On the other side, the block was fixed with 2 fixation screws inserted in the extremities of the graft. Four weeks later, the fixation screws were replaced with 3 dental implants. The loading procedure (delayed implant placement group) was performed 2 days later, as described for the simultaneous implant placement sites. The animals were sacrificed 12 weeks after the grafting procedure. Implant stability was measured through resonance frequency analysis. The bone volume and density were assessed on computed tomography. The bone to implant contact and bone area in a region of interest were evaluated on histologic slides. RESULTS: The implant stability quotient showed statistical significance in favor of the delayed loaded grafts (P = .001). The bone-to-implant contact (P = .008) and bone area in a region of interest (P = 0.005) were significantly greater in the delayed group. Nevertheless, no difference was found in terms of graft volume and density between the early loaded and delayed-loaded approaches. CONCLUSIONS: The protocol in which the implant and bone graft were given delayed loading allows for effective quality of implant osseointegration and stabilization, with healing and remodeling occurring in areas near the implant resulting in denser bone architecture.
Assuntos
Aumento do Rebordo Alveolar/métodos , Transplante Ósseo , Implantação Dentária Endóssea , Prótese Dentária Fixada por Implante , Osseointegração , Análise de Variância , Animais , Densidade Óssea , Parafusos Ósseos , Dente Suporte , Retenção em Prótese Dentária , Análise do Estresse Dentário , Cães , Masculino , Probabilidade , Estatísticas não Paramétricas , Fatores de Tempo , Tomografia Computadorizada por Raios X , VibraçãoRESUMO
BACKGROUND: Previous studies have shown that membrane elevation results in predictable bone formation in the maxillary sinus provided that implants can be placed as tent poles. In situations with an extremely thin residual crest which impairs implant placement, it is possible that a space-making device can be used under the sinus membrane to promote bone formation prior to placement of implants. PURPOSE: The present study was conducted to test the hypothesis that the use of a space-making device for elevation of the sinus membrane will result in predictable bone formation at the maxillary sinus floor to allow placement of dental implants. MATERIALS AND METHODS: Eight tufted capuchin primates underwent bilateral sinus membrane elevation surgery, and a bioresorbable space-making device, about 6 mm wide and 6 mm in height, was placed below the elevated membrane on the sinus floor. An oxidized implant (Nobel Biocare AB, Gothenburg, Sweden) was installed in the residual bone protruding into the created space at one side while the other side was left without an implant. Four animals were sacrificed after 6 months of healing. The remaining four animals received a second implant in the side with a space-making device only and followed for another 3 months before sacrifice. Implant stability was assessed through resonance frequency analysis (RFA) using the Osstell (Osstell AB, Gothenburg, Sweden) at installation, 6 months and 9 months after the first surgery. The bone-implant contact (BIC) and bone area inside the threads (BA) were histometrically evaluated in ground sections. RESULTS: Histologically there were only minor or no signs of bone formation in the sites with a space-making device only. Sites with simultaneous implant placement showed bone formation along the implant surface. Sites with delayed implant placement showed minor or no bone formation and/or formation of a dense fibrous tissue along the apical part of the implant surface. In the latter group the apical part of the implant was not covered with the membrane but protruded into the sinus cavity. CONCLUSIONS: The use of a space-making device, with the design used in the present study, does not result in bone formation at the sinus floor. However, membrane elevation and simultaneous placement of the device and an implant does result in bone formation at the implant surface while sites with implants placed 6 months after membrane elevation show only small amounts of bone formation. It is suggested that lack of stabilization of the device and/or a too extensive elevation of the membrane may explain the results.
Assuntos
Implantação Dentária Endóssea , Seio Maxilar/cirurgia , Procedimentos Cirúrgicos Pré-Protéticos Bucais/instrumentação , Osteogênese , Animais , Cebus , Retenção em Prótese Dentária , Masculino , Mucosa Nasal , Osseointegração , Poliésteres , VibraçãoRESUMO
The information concerning the molecular events taking place in onlay bone grafts are still incipient. The objective of the present study is to correlate the effects of perforation of resident bone bed on (1) the timing of onlay autogenous graft revascularization; (2) the maintenance of volume/density of the graft (assessed through tomography); and (3) the occurrence of bone remodeling proteins (using immunohistochemistry technique) delivered in the graft. Thirty-six New Zealand White rabbits were subjected to iliac crest onlay bone grafting on both sides of the mandible. The bone bed was drill-perforated on one side aiming at accelerating revascularization, whereas on the other side it was kept intact. After grafts fixation and flaps suture all animals were submitted to tomography on both mandible sites. Six animals were sacrificed, respectively, at 3, 5, 7, 10, 20 and 60 days after surgery. A second tomography was taken just before sacrifice. Histological slides were prepared from each grafted site for both immunohistochemistry analysis [osteopontin, osteocalcin, type I collagen and vascular endothelial growth factor (VEGF) anti-bodies] and histometric analysis. The values on bone volume measured on tomography showed no statistic significance (P>or=0.05) between perforated and intact sites. Grafts placed on perforated beds showed higher bone density values compared with non-perforated ones at 3 days (PAssuntos
Remodelação Óssea
, Transplante Ósseo/fisiologia
, Mandíbula/cirurgia
, Neovascularização Fisiológica
, Processo Alveolar/irrigação sanguínea
, Animais
, Densidade Óssea
, Colágeno Tipo I/análise
, Ílio/cirurgia
, Imuno-Histoquímica
, Osteocalcina/análise
, Osteopontina/análise
, Coelhos
, Tomografia por Raios X
, Fator A de Crescimento do Endotélio Vascular/análise
RESUMO
PURPOSE: Bone maintenance after mandibular reconstruction with autogenous iliac crest may be disappointing due to extensive resorption in the long term. The potential of the guided-bone regeneration (GBR) technique to enhance the healing process in segmental defects lacks comprehensive scientific documentation. This study aimed to investigate the influence of polylactide membrane permeability on the fate of iliac bone graft (BG) used to treat mandibular segmental defects. MATERIALS AND METHODS: Unilateral 10-mm-wide segmental defects were created through the mandibles of 34 mongrel dogs. All defects were mechanically stabilized, and the animals were divided into 6 treatment groups: control, BG alone, microporous membrane (poly L/DL-lactide 80/20%) (Mi); Mi plus BG; microporous laser-perforated (15 cm(2) ratio) membrane (Mip), and Mip plus BG. Calcein fluorochrome was injected intravenously at 3 months, and animal euthanasia was carried out at 6 months postoperatively. RESULTS: Histomorphometry showed that BG protected by Mip was consistently related to larger amounts of bone compared with other groups (P Assuntos
Regeneração Óssea
, Transplante Ósseo/métodos
, Regeneração Tecidual Guiada Periodontal/métodos
, Mandíbula/cirurgia
, Membranas Artificiais
, Implantes Absorvíveis
, Análise de Variância
, Animais
, Cães
, Masculino
, Permeabilidade
, Poliésteres
, Porosidade
, Procedimentos de Cirurgia Plástica/métodos
RESUMO
BACKGROUND: Recent clinical studies have described maxillary sinus floor augmentation by simply elevating the maxillary sinus membrane without the use of adjunctive grafting materials. PURPOSE: This experimental study aimed at comparing the histologic outcomes of sinus membrane elevation and simultaneous placement of implants with and without adjunctive autogenous bone grafts. The purpose was also to investigate the role played by the implant surface in osseointegration under such circumstances. MATERIALS AND METHODS: Four tufted capuchin primates had all upper premolars and the first molar extracted bilaterally. Four months later, the animals underwent maxillary sinus membrane elevation surgery using a replaceable bone window technique. The schneiderian membrane was kept elevated by insertion of two implants (turned and oxidized, Brånemark System, Nobel Biocare AB, Göteborg, Sweden) in both sinuses. The right sinus was left with no additional treatment, whereas the left sinus was filled with autogenous bone graft. Implant stability was assessed through resonance frequency analysis (Osstell, Integration Diagnostics AB, Göteborg, Sweden) at installation and at sacrifice. The pattern of bone formation in the experimental sites and related to the different implant surfaces was investigated using fluorochromes. The animals were sacrificed 6 months after the maxillary sinus floor augmentation procedure for histology and histomorphometry (bone-implant contact, bone area in threads, and bone area in rectangle). RESULTS: The results showed no differences between membrane-elevated and grafted sites regarding implant stability, bone-implant contacts, and bone area within and outside implant threads. The oxidized implants exhibited improved integration compared with turned ones as higher values of bone-implant contact and bone area within threads were observed. CONCLUSIONS: The amount of augmented bone tissue in the maxillary sinus after sinus membrane elevation with or without adjunctive autogenous bone grafts does not differ after 6 months of healing. New bone is frequently deposited in contact with the schneiderian membrane in coagulum-alone sites, indicating the osteoinductive potential of the membrane. Oxidized implants show a stronger bone tissue response than turned implants in sinus floor augmentation procedures.
Assuntos
Implantação Dentária Endóssea/métodos , Seio Maxilar/cirurgia , Osseointegração , Animais , Transplante Ósseo/métodos , Cebus , Masculino , Membranas , Propriedades de SuperfícieRESUMO
BACKGROUND: Since the discovery of bone morphogenetic proteins (BMPs), the number of related studies has increased substantially, and more recent outcomes have cast encouraging perspectives on their use in reconstructive surgery. PURPOSE: The aim of the present review was to summarize the present knowledge about the use of BMPs in conjunction with dental implants based on the literature. MATERIALS AND METHODS: Scientific articles dealing with the use of growth factors and bone healing with or without dental implants were searched for on MEDLINE and critically scrutinized. RESULTS: Thirty-nine scientific reports formed the base for the present review. Whereas the osteoinductive capability of BMPs is well documented, studies on their effects in implant dentistry are still incipient. Preclinical and clinical studies did not show outstandingly good outcomes of the application of BMPs compared with conventional treatments or controls. CONCLUSIONS: The number of studies in the field of dental implantology in which BMPs have been used is still too small for establishing clinical protocols of their use in order to improve a recipient bone bed prior to implant placement or to enhance the integration process of an implant.